Oregon State University will host a workshop covering ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) and scanning tunneling microscopy (STM) techniques on Wednesday, Sept. 6, in conjunction with the 2017 Symposium of the Pacific Northwest Chapter of the American Vacuum Society.

The workshop, led by Greg Herman, professor of chemical engineering, will include invited lecturers, tutorials and a laboratory visit, highlighting new AP-XPS/AP-STM and variable-temperature STM capabilities at Oregon State and similar capabilities in the region. Registration is free. (Please indicate your interest in participating in the symposium on your symposium registration form.)

Tentative Schedule

Introduction (1:30-1:35)
Liney Arnadottir, Oregon State University

A Tutorial in XPS:  How we got here, what we’re doing, and where are we going? (1:35-2:05)
William F. Stickle, HP Inc.

Introduction to Scanning Tunneling Microscopy (STM) (2:05-2:35)
David Y. Lee, Washington State University 

System Solutions for Laboratory Based Ambient Pressure Photoelectron Spectroscopy (2:35-3:05)
Brandon Giles, Scienta Omicron

EnviroESCATM – Routine surface analysis under environmental conditions (3:05-3:35) 
Thomas Schulmeyer, SPECS

Transition metal redox and hydroxylation on epitaxial oxide surfaces (3:35-4:20)
Kelsey Stoerzinger, Pacific Northwest National Laboratory 

Surface and Interface Science for the 21st century: wet, warm and dense (4:20-5:20)
Miquel Salmeron, Lawrence Berkeley National Laboratory 

Oregon State Capabilities and NNCI (5:20-5:30)
Greg Herman, Oregon State University 

Guest Speaker Abstracts and Bios

A Tutorial in XPS:  How we got here, what we’re doing, and where are we going?

William F. Stickle, HP Inc. 

Abstract: X-ray photoelectron spectroscopy is a surface chemical analysis technique that has been in wide use for many decades. This tutorial is intended to be a brief look at the basic principles of the technique, experimental procedures and a discussion of data interpretation. The fundamental principles of XPS are little changed over time, but instrumentation, experimental procedures and methods of data analysis and interpretation have advanced to meet the needs of the frontiers of materials analysis. This tutorial will also expand on how the essentials of XPS are now routinely applied and include a glimpse to the future.

Bio: William F. Stickle is a senior member of the technical staff in HP’s Analytical and Developmental Lab in Corvallis, Oregon. He received his B.S. in Chemistry from Virginia Polytechnic Institute and State University in 1977 and his Ph.D. in Chemistry from the University of Notre Dame in 1983.  He began his industrial career with the Physical Electronics Division of Perkin-Elmer as a laboratory scientist in their analytical lab. Working in PHI's laboratory in Mountain View, California, and later in Eden Prairie, Minnesota, he was eventually promoted to senior staff scientist. Bill joined Hewlett-Packard in 1995 and is the worldwide technical lead for surface analysis in HP. He has used a wide variety of surface analytical techniques for problem solving and materials characterization including XPS, AES, TOF SIMS, dynamic-SIMS, RBS, and SPM.  Bill has authored or co-authored more than 100 papers, talks, book chapters and books related to applications of surface analysis covering a wide variety of material systems.  Bill was named a Fellow of AVS in 2012; he is also involved with ASTM E-42 and ISO Technical Committee 201-Surface Chemical Analysis and serves as an U.S. expert for several other sub-committees.

Introduction to Scanning Tunneling Microscopy (STM)

David Y. Lee, Assistant Professor, Department of Chemistry, Washington State University

Abstract: A concise introduction to STM is offered in this presentation, including the general theory about electron tunneling and the instrument’s history, functionality and resolution capability. Scanning tunneling spectroscopy (STS) is also discussed using organometallic monolayers as examples.

Bio: Professor Lee earned his B.S. in Chemistry and M.S. in Synthetic Organic Chemistry from Rochester Institute of Technology before completing his Ph.D. degree at Cornell University under the direction Prof. Paul L. Houston in Physical Chemistry.  After graduate school, he joined Prof. S. Alex Kandel’s Scanning Tunneling Microscopy (STM) group at University of Notre Dame as a post-doctoral fellow. Prof. Lee started his research program at WSU in 2014 with current research projects center around in-situ investigation of surface chemical changes that occur when materials interact with photons and with gas-phase reactants. Multiple techniques, including molecular beams, laser stimulation/photolysis and X-ray photoelectron spectroscopy, are employed associatively with STM to study these topics from the perspective of fundamental physical chemistry.

System Solutions for Laboratory Based Ambient Pressure Photoelectron Spectroscopy

Brandon Giles, Scienta Omicron

Abstract: Ambient pressure photoelectron spectroscopy (APPES) is a rapidly developing technique that has been used in wide range of scientific studies with applications as diverse as heterogeneous catalysis, to the development of fuel cells and batteries, to advances in biomaterials and environmental chemistry. To meet the research challenges associated with these endeavours, Scienta Omicron has developed the HiPP-lab, a laboratory based system solution for APPES intended to facilitate a wide range of possible experiments for the end user. The system can be equipped with one of multiple state of the art electron energy analysers capable of measuring samples with a surrounding gas pressure in the mbar range. 

The design and performance of these analysers and their integration into the HiPP-lab will be discussed. Advantages of the modular based design of the HiPP-lab will also be examined. Finally, specific application data acquired using both the Scienta Omicron HiPP-2 analyser, (designed for high energy X-ray photoelectron spectroscopy (HAXPES), and the Scienta Omicron HiPP-3 analyser (designed specifically for XPS energies) will be presented.

Bio: Brandon Giles joined Scienta Omicron in June 2017. He received his PhD in Materials Science and Engineering from the Ohio State University, working under the guidance of Professor Roberto Myers. Dr. Giles has an extensive background in materials characterization, most recently developing the opto-thermal measurement technique, which is used to study magnon spin transport in various magnetic insulators. Prior to his involvement in spin transport measurements, Dr. Giles worked with Professor Michael Crommie at the University of California, Berkeley where he characterized mechanically exfoliated and CVD grown graphene using scanning tunnelling microscopy.

Enviro-ESCATM – Routine surface analysis under environmental conditions 

Thomas Schulmeyer, SPECS-TII Inc., Mansfield, Massachussetts (USA)

Stephan Bahr, Paul Dietrich, Michael Meyer, Andreas Thissen, SPECS Surface Nano Analysis GmbH – Berlin (Germany)

Abstract: For many decades XPS (or ESCA) has been the well-accepted standard method for non-destructive chemical analysis of solid surfaces. To fulfill this task existing ESCA tools combine reliable quantitative chemical analysis with comfortable sample handling concepts, integrated into fully automated compact designs.

Over the last few years, it has been possible to develop XPS systems that can work far beyond the standard conditions of high or ultrahigh vacuum. Near Ambient Pressure (NAP) XPS has become a fast-growing field in research inspiring many scientist to transfer the method to completely new fields of application. By crossing the pressure gap, new insights in complicated materials systems have become possible using either synchrotron radiation or laboratory X-ray monochromators as excitation sources under NAP conditions.

Finding a way to compensate for the environmental charge is the next step. Generally, insulators will positively charge in XPS due to the irradiation with X-rays and the emission of photoelectrons. Without compensation this effect leads to strong continuous shifts and asymmetric line shapes of emission in the spectra. To perform an exact characterization and quantification of strongly insulating materials different concepts of charge compensation or neutralization have been developed over the last decades. During the last months, measurements on insulators have shown, that they can be measured with exception in surrounding pressures of a couple of mbar without any charging. This new technique of charge neutralization is named Environmental Charge Compensation (ECC). This presentation summarizes results of measurements on insulating samples, showing the resulting spectroscopic resolution for C1s and O1s emission lines. 

Bio: Thomas Schulmeyer joined SPECS in 2010, after completing two years of postdoctoral research at the University of Arizona, Tucson. Prior to that he spent four years in the semiconductor industry at Global Foundries (formerly AMD). He earned his Ph.D. in 2005 from the University of Technology, Darmstadt, Germany, where his emphasis was photoemission spectroscopy. 

Transition metal redox and hydroxylation on epitaxial oxide surfaces

Kelsey A. Stoerzinger, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory

Abstract: Transition metal oxides present a promising alternative to noble metals for oxygen electrocatalysis. However, a lack of fundamental understanding of the reaction mechanism has hindered their rational design. Investigation of model epitaxial oxide thin films allows spectroscopic examinations of their chemical speciation in an aqueous environment using ambient pressure X-ray photoelectron spectroscopy. By quantifying the formation of hydroxyl groups, we compare the relative affinity of different surfaces for this key reaction intermediate in oxygen electrocatalysis. Understanding the electronic structure of oxides in an aqueous environment is also critical for promoting charge transfer reactions in both electrocatalytic and photocatalytic reactions. To this end, we investigate changes in the electronic structure as a function of the oxygen and water chemical potential, enabling comparison with the metal redox potential and catalytic activity.

Bio: Kelsey is a Linus Pauling Postdoctoral Fellow at Pacific Northwest National Laboratory, interested in the chemistry at (photo)electrochemical interfaces and its role in dictating catalyst performance. As an NSF Graduate Research Fellow, Kelsey completed her doctoral studies in Materials Science and Engineering at MIT, studying oxygen electrocatalysis on model thin film oxide catalysts. She received an M.Phil. in Physics from the University of Cambridge as a Churchill Scholar and a B.S. in Materials Science and Engineering from Northwestern University.

Surface and Interface Science for the 21st century: wet, warm and dense

Miquel B. Salmeron, Senior Scientist, Materials Science Division, Lawrence Berkeley National Laboratory

Abstract: Over the past century the science of surfaces has undergone an enormous progress. The atomic and electronic structure, reactivity, and dynamics of many material surfaces have been uncovered. Several Nobel prizes have marked the great accomplishments of our predecessors, from I. Langmuir in 1932 to G. Ertl in 2007. The nature of many surface science imaging and spectroscopy techniques has constrained its use to ultra-high vacuum environments, and often under cryogenic temperature to achieve measurable coverage of weakly bound adsorbates. And yet practical surfaces are surrounded by gases and liquids at ambient conditions of pressure and temperature. Under these conditions the surfaces are covered with dense layers of adsorbate in equilibrium with the gas, while at the same time the ambient temperature unlocks kinetic processes that are frozen at low temperatures. One consequence of this is that under realistic conditions the structure of surfaces can be very different from that obtained after preparation in high vacuum with traditional Surface Science techniques. I will review how the use of Ambient Pressure techniques, STM and XPS in particular, has changed our view of surfaces with examples that include O2, H2O, CO gases on substrates like Pt and Cu. Prospects for similar studies of the solid-liquid interface, a new frontier in the field, and their impact in environmental science, electrochemistry and energy storage will be discussed. 

Bio: Miquel B. Salmeron is a senior scientist in the Materials Science Division of the Lawrence Berkeley National Laboratory and adjunct professor in the Materials Science and Engineering Department at the University of California, Berkeley. His research focuses on the atomic structure and on the electronic, mechanical and chemical properties of surfaces, including adsorbed atoms and molecules, their diffusion and film growth. He developed instrumentation that can operate under ambient conditions of gases and liquids, including Scanning Tunneling and Atomic Force Microscopy and Ambient Pressure Photoelectron Spectroscopy. He is a Fellow of the American Physical Society and American Vacuum Society. He has received the Davisson-Germer Prize in Surface Physics from the American Physical Society, the Medard Welch Award of the American Vacuum Society, the Langmuir Lectureship Award of the American Chemical Society, and the MRS Medal. In 2016, he received the Lifetime Accomplishment Award from the Lawrence Berkeley National Laboratory. 

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